Re: brake rotors

[Stacy Faught <slfaught@domain.elided>]

This is as close to 100% correct as you are going to get.  The rapid machinig process that
rotors go through builds internal stress into the material.  In precision components, such as 
aircraft turbine disks, the part is machined to a 'sonic shape' before it is put into a heat treat 
cycle, where the metal is heated to about 90% of melt temperature so that all the internal 
stress is relieved.  Then the final .500" is machined off to create the end product.  When making
brake rotors, it is simply not cost effective to heat treat the rotors, since it takes about 8 hours in 
an oven to do it properly.  
The machining process is very cool, by the way---they don't use any coolant on the tool, and the tool
is HUGE--at least 1/2 inch.  The part spins very fast, and the resulting heat at the contact point of the
tool and the part creates a plasma layer that allows the tool to hog out big chucks of steel (or iron, or titanium, ect)
without wearing the tool at all.  The cool part of all this is that big glowing chunks of metal are being flayed 
off and flung all about the enclosed mill.  Quite a sight.




>Date: Thu, 19 Dec 2002 20:27:59 -0500 (EST)
>From: Richard Welty <rwelty@domain.elided>
>Subject: Re: brake rotors
>
>On Thu, 19 Dec 2002 19:49:08 -0500 Ferdinando Di Matteo <aroctech@domain.elided> wrote:
>> Here is a question for all of you Digesti.  What make rotors warp?  Fred
>
>one theory i've been told for why cheap rotors warp more than good ones is
>that the manufacturing process they go through doesn't provide for proper
>cooling of the blanks and for proper stress relief during that cooling
>process. the result is that you have a rotor with the pattern for the warp
>effectively  "embedded" in it.
>
>richard
>- --
>Richard Welty                                         rwelty@domain.elided
>Averill Park Networking                                         518-573-7592
>           Unix, Linux, IP Network Engineering, Security
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